Problem With MTD mower

[97prizm]

I have a four year old MTD push mower that my parents purchased at Home Depot years ago. I don't really remember if it excessively vibrated when new but even with a new balanced and sharpened blade It still shakes bad enough to make your arm sore after an hours worth of mowing. I replaced the original blade mount that connects to the shaft as the original had the "teeth" wear off. Any thoughts? Could the shaft be bent? A mowing shop said it was balanced correctly.

 

[spasm3]

I suspect it has hit something and the crank shaft is bent. i would be curious to know if it shakes when you run it without the blade on it.

 

[boraticus]

How are the motor mount bolts? Are they all tight?

Wouldn't be too hard to check the crank to see if it's bent or not. Turn the machine on it's side, remove the blade and clamp something for reference to the side of the deck that just barely reaches from the side of the deck to the side of the crank. Remove the spark plug, and pull the pull start slowly watching how the shaft relates to the piece that's clamped to the deck. If the shaft moves either toward or away from the reference piece, the crank might be bent.

 

[yeehaw1960]

Probably bent shaft. The shop will tell you to throw it away, but don't do it. Remove spark plug like mentioned above. Turn it on it's side (muffler up). If the carb is on the other side, you can save the air filter by pinching off the gas line and running the engine out of gas before turning it onto it's side. Take the blade and mount off. Run a string from a (tied onto) front wheel adjuster past the shaft and anchor with your finger on the other side of the frame. Pull the rope and note where the shaft is high. Line up on it and whack it with a decent size hammer (one time) and recheck. You'll never get it perfect so settle for close. DON'T heat the shaft and attempt to true it up. There is a lot of stress on it anyway and you don't want to lose any of it's temper by heating it up.

Don't hit it right on the tip of the shaft or you'll mushroom it and make the blade mount not slide on easily. I've done this many, many times without incident.